The present invention relates to a substation component for the power generator installed in the power plants such as thermal electric power plants, nuclear power plants and hydro-electric power plants, especially to a switchgear installed on the main circuit from the generators to the transformers.
As for the switchgear installed on the main circuit from the generators to the transformers, for example, what is well known is disclosed in Japanese Patent Laid-Open Number 61-1218 (1986). The switchgear disclosed in this document is composed so that the components for the individual phases are separated and the switchgears are contained in the individual exterior covering, respectively. The upper-side of the exterior covering containing the switchgear is connected through the exterior covering containing the connecting bus tie to the exterior covering containing the disconnecting switch in step-wise configuration.
In this kind of conventional switchgear, the contact makers of the breaker part of the disconnecting switch are made contact to and leave from each other in responsive to the voltage value in the main circuit. In order to measure the voltage value in the main circuit, plural instrumentation transformers are installed at the switchgears. Those instrumentation transformers are installed in separate containers other than the containers containing the breaker part of the disconnecting switch.
In recent years, many efforts are made for integrating components into a unified and composite unit in order to downsize the switchgears and reduce their cost. Along with this trend, there arises strong request to accommodate plural instrumentation transformers in the container including the breaker part of the disconnecting switches. However, there are still unsolved problems regarding the method for the layout of plural instrumentation transformers in three containers arranged together.
A major object of the present invention is to provide a switchgear enabling to increase the working efficiency for the installation operation of the instrumentation transformers into the containers and the withdrawal operation of the instrumentation transformers from the containers.
The present invention is characterized by such an arrangement of plural instrumentation transformers for measuring the voltage in the main circuit as located within the container in the midst of containers arranged together.
According to the above described embodiment, as plural instrumentation transformers are arranged within the container located in the midst of the center among the containers arranged together, the installation operation of the instrumentation transformers into the containers and the withdrawal operation of the instrumentation transformers 6a to 6d from the containers may be applied only to the container 15b, and the installation and withdrawal operation at the other containers may be done simply by wiring the primary-side lead lines. Owing to this configuration, the work load and work time for the installation operation of the instrumentation transformers 6a to 6d into the containers and the withdrawal operation the instrumentation transformers 6a to 6d from the containers can be reduced to a large extent.
According to the present invention, it is easy to route the primary-side lead line of the instrumentation transformer from the container located at the center to the containers located at both ends. That is, in case that the instrumentation transformers are installed in the containers located at both ends, there occurs a part in which a couple of primary-side lead lines for the instrumentation transformers are required to be routed. As it is necessary to establish an enough insulation distance between two lead lines in this configuration, the structure of routing the primary-side lead lines may be complicated or the container may be upsized. In contrast, in this invention, as plural instrumentation transformers are arranged within the container located in the midst among the containers, the primary-side lead lines for the instrumentation transformers can be accommodated by a single cable extended from the container located in the midst to the containers located at both ends. Thus, it will be appreciated that the complexity in the routing configuration for the primary-side lead lines and the up sizing of the containers can be reduced.
A couple of coadjacent containers among three containers arranged together are linked by an insulating tube. The primary-side lead line of the instrumentation transformer corresponding to the phase for the containers located at both ends of three containers arranged together is made routed from the container located in the midst among three containers through the insulating tube to the corresponding container located at one of both ends of containers. The reason why the insulation tube is used for linking the containers is to prevent the cyclic current from flowing between the containers.
A breaker part of the disconnecting switch for disconnecting electrically the main circuit is installed at the individual containers arranged together. The breaker part is insulated by the insulating gas such as sulfur hexafluoride, and has a contact makers operated by the manipulator so as to contact to and leave from each other. A switching part of the disconnecting switch, a switching part of the earthing switch and an arrestor, connected electrically to the main circuit, are arranged in three containers arranged together, individually.
The height of the container located in the midst among three containers arranged together is made larger than the height of the other containers in order to establish an enough insulation distance between plural instrumentation transformers and the other components. The primary-side of plural instrumentation transformers is configured with open-delta connection or star connection. The plural instrumentation transformers are supported so as to be suspended down from the ceiling board installed above the container. The arresters are also supported so as to be suspended down from the ceiling board installed above the container.